remove facebook comment because it will end to use: https://developers.facebook.com/docs/plugins/embedded-comments

Author: landofcoder

Model/Config/Source/CommentType.php

@@ -31,8 +31,8 @@ public function toOptionArray()
     {
         return [
             ['value' => 'default', 'label' => __('Default')],
-            ['value' => 'disqus', 'label' => __('Disqus')],
-            ['value' => 'facebook', 'label' => __('Facebook')]
+            ['value' => 'disqus', 'label' => __('Disqus')]
+            //['value' => 'facebook', 'label' => __('Facebook')]
         ];
     }